Method of picture reproduction with variable reproduction scale

ABSTRACT

A method of picture reproduction with variable reproduction scale. The original picture is scanned to obtain picture signals to be recorded, the picture signals are written into a memory with addressing in synchronization with timing pulses, and then the original picture is reproduced by reading out the picture signals from the memory. In this method a variable magnification scale can be obtained by compressing or elongating the picture signals with the use of insert pulses different from the usual timing pulses, the insert pulses being inserted among the timing pulses in proportion to the magnification scale required.

The present invention relates to a method of picture reproduction withvariable reproduction scale, and more particularly to a method ofpicture reproduction using a color scanner, a facsimile producer and thelike, with variable magnification scale between the original and thereproduction pictures by picture scanning and recording.

In the art of picture reproduction, many methods for changingmagnification of the picture have been developed. Conventional methodsfor changing magnification in such picture reproducing methods includethe following.

In, a first mechanical method, magnification is changed by usingoriginal picture and recording cylinders of different diameter. In thismethod, however, the ratio between the diameters of the two cylindersdetermines the magnification. Consequently, a different cylinder isrequired for each magnification factor. This means high cost, and therange of magnification factors is limited by the availability ofcylinders.

In another mechanical method, magnification is changed by varying therelative rotation speeds of two cylinders instead of using cylinders ofdifferent diameter. In this case the ratio between such rotation speedsmust be an integer so as to easily synchronize the phase of the originalpicture scanning system with the recording system with scanning. Thismeans corresponding limitation of magnification factors. This defect hasbeen removed by the use of a memory, resulting in a method of picturereproduction with variable reproduction scale, that is, in a method ofpicture reproduction comprising rotating simultaneously two cylindersfor an original picture and a recording film, first storing picturesignals picked up by scanning the original picture on the picturecylinder in the memory, and then recording or reproducing the pictureonto the recording film on the recording cylinder by properly readingout the picture signals from the memory. In this system themagnification scale may be continuously varied by varying the frequencyof the sampling pulses.

However, this method has disadvantages. Supposing that the reading outspeed is defined, the number of sampling pulses or the frequencies forwriting into the memory should be increased when enlarging. Accordingly,a special analog-digital converter having very wide frequency range andhigh converting speed disposed prior to the memory is required. However,such a converter is not available on the market, and a color correctioncircuit having wide frequency range is also required. This means highcost.

In accordance with the present invention, a method of picturereproduction with variable reproduction scale is provided, which is freefrom the above-mentioned defects of the prior art and comprises tworotating cylinders with a common axis for an original picture and arecording film, first storing picture signals picked up by scanning theoriginal picture on the picture cylinder into a memory, and thenreproducing the picture onto the recording film on the recordingcylinder by reading out the picture signals from the memory, andinserting other pulses generated by a magnification scale set up meansamong address pulses for of the memory when reading out the picturesignals from the memory or when writing the picture signals into thememory.

According to the present invention it is unnecessary to reduce orenlarge the basic timing pulse intervals in proportion to the reducingor enlarging magnification scale when writing and reading out thepicture signals or from the memory. Hence, the increase of the frequencyrange does not extend to the whole machine. Further, there is no need touse any special high-speed analog-digital converter. Usualanalog-digital converters on the market can be used in accordance withthe present invention, and no wider frequency range of the colorcorrection circuit prior to the memory is required. Consequently, a veryeconomical picture reproduction method with variable reproduction scalecan be provided according to the present invention.

In order that the invention may be better understood, one embodimentwill now be described with reference to the accompanying drawings, inwhich:

FIG. 1 is a block diagram of a method of picture reproduction withvariable reproduction scale in accordance with the present invention;

FIG. 2 is a time chart of electric signals when reproductionmagnification scale is less than unity;

FIG. 3 is a time chart of electric signals when reproductionmagnifiction scale is greater than unity; and

FIG. 4 is a block diagram of a magnification scale set up means of themethod shown in FIG. 1.

Referring to the drawings, in FIG. 1, an original picture cylinder 1 anda recording film cylinder 2 are rotated by an electric motor 3 via arotary shaft 4. An original picture on the original picture cylinder 1is scanned in the right hand direction by a scanning head 6 moved in thedirection of the cyinders' axis by an electric motor 5. Picture signalse₁, inlcuding unsharp signals and the like, converted into colorseparation signals by the scanning head 6, are fed to a color correctioncircuit 7. Then the color correction circuit 7 puts out correctedpicture signals e₂.

The color correction circuit 7 includes a masking circuit correctingimpurities of color ink components and a contrast compensating circuitand the like. Conventional color correction circuits, for example, usedin scanners and the like can be used in the present invention. Hence,further description of such color correction circuits is unnecessaryhere.

The picture signals e₂ come from the color correction circuit 7 arechanged to digital form in synchronization with regular timing pulses g₁generated by a pulse generator 8 comprising a rotary encoder and soforth, and the rotary encoder is coaxially combined with the originalpicture and recording cylinders.

Firstly, when the reproducing magnification scale is unity, i.e., actualsize, the picture signals e₂ are converted into digital picture signalse₃ in the analog-digital converter 9, hereinafter referred to as the A-Dconverter, in synchronization with the timing pulses g₁ coming from thepulse generator 8. Writing or storing of the digital picture signals e₃into a memory 11 is performed according to writing address signals g₂generated by an address signal generator 10, and the writing addresssignals g₂, in case of 1-1 scale, address memory locations withaddresses the same as the serial numbers of the corresponding timingpulses g₁ following the start of scanning.

The memory has more than enough capacity to store the digital picturesignals e₃ picked up by scanning the original picture in one cycle, thatis, in one revolution circumference of the picture cylinder 1. In FIG.1, the signal paths drawn in solid lines show the writing mode and thesignal paths drawn in dotted lines show the reading mode.

In actual use two independent memory units 11 are provided and the inputand output to them is switched by switching means so that reading of oneline out from one memory unit and writing of the next line into theother memory unit are preformed simultaneously, and thus picturereproduction speed is twice what it would be if no such switching wereperformed. Therefore for alternate lines the switching system changesover the pair of memory units so that each is written into and is readout from alternately. However, for ease of explanation further mentionof this duplexing of memory unit 11 will be omitted from thisspecification.

The reading process of the picture signals from the memory 11 is startedby the start pulse corresponding to the start position of one cycle ofreproduction. Reading out is performed in synchronization with readingout address signals g₂ ' generated by the address signal generator 10,and the reading out address signals g₂ ' address, the in the same manneras the writing in case of 1-1 scale, memory locations with addresses thesame as the serial numbers of the corresponding timing pulses g₁following the start of scanning. The memory 11 puts out digitalreproduction picture signals e₄.

The digital reproductuon picture signals e₄ are changed to analogpicture signals e₅ in a digital-analog converter 12, hereinafterreferred to D-A converter, in synchronization with the timing pulses g₁,and then the analog picture signals e₅ are fed to an output controlcircuit 13.

The output control circuit 13 controls a light source of the recordinghead 15, and modulates its optical output. This recording head is movedin the right hand direction with the same speed, in case of 1-1 scale,as the scanning head 6 by an electric motor 14, in in unison with to theoutput picture signals e₆ of the output control circuit 13, so that thepicture reproduction of actual size is obtained on the recording films.

As above-described, in case of 1-1, the writing and reading-out speedsof the picture signals into or from the memory 11 are controlled to beequal and the sliding speeds of both the heads are the same, and therebythe picture reproduction of actual 1-1 scale in both the longitudinaland the transverse directions is obtained. The recording picture signalse₄, e₅, and e₆ are, however, delayed precisely one cycle with respect tothe scanning picture signals e₁, e₂, and e₃.

For reproducing the original picture on a reduced scale the scanninghead 6 is advanced forward faster than the recording head 15 by theprescribed reduction scale, which is performed, for example, bycontrolling the rotational speed of the electric motor 5 by means of amagnification scale set-up means 16.

Further, FIG. 2 shows a time chart showing the signals for writing andreading out immediately after the respective starts, in which thesynchronizing signals g₁ are shown in common.

In writing of the picture signals into the memory 11, the correctedanalog picture signals e₂ coming from the color correction circuit 7 areconverted into the digital picture signals e₃ in synchronization withthe timing signals g₁ in the A-D converter 9 and then are stored in thememory 11.

Parenthetically, in FIG. 2 as well as FIG. 3, the digital picturesignals e₃ are shown as bar samples of the analog picture signals e₂,but actually they consist of binary codes, and the reproduction digitalpicture signals e₄ are shown as well in this way.

Storing, i.e. writing of, the picture signals to be recorded into thememory 11 is performed in synchronization with the writing which addressmemory locations with addresses the same as the serial numbers of thecorresponding timing pulses g₁ following the start of scanning.

On the other hand, in reading out, insert pulses g₃ produced by themagnification set up means 16 are inserted among the timing signals g₁at intervals corresponding to the magnification scale, and then theaddress signal generator 10 puts out the different reading addresssignals g₂ ' differing differ from those for writing.

The insert pulses g₃ serve to produce the address signals g₂ ' whichpermit to advance, i.e., to increase by one, the address of the memorylocation addressed by the timing pulses of g₁ following the insert pulseof g₃, that is, to skip one address. Thereby the reproduction digitalpicture signals e₄ read out from the memory 11 are compressed or reducedwith respect to the time axis, i.e., in the direction of thecircumference of the recording cylinder.

The compressed reproduction digital picture signals e₄ are fed to theD-A converter 12 in which the signals read out by means of addressing bythe extra insert pulses g₃ are not synchronized with the timing signalsg₁. Consequently they cannot be converted into analog signals and so areerased. As a result, the reduced reproduction analog picture signals e₅are obtained.

Alternatively, when the picture size is to be enlarged, in writing, theinsert pulses g₃ generated by the magnification scale set up means 16are fed to the address signal generator 10. The address signal generator10 generates the address signals g₂ addressing the memory, ashereinbefore described. When the extra insert pulses g₃ are insertedamong the timing signals g₁, the address pulses having the next addressnumbers are produced by the address signal generator according to theinsert pulses g₃, and the same picture signals as the previous picturesignals from the A-D converter 9 written to the memory locationsaddressed by the previous address signals are written to the next memorylocations addressed by the newly produced address pulses.

That is, the A-D converter 9 samples the analog picture signals e₂ issynchronization with the timing signals g₁, converts them into thedigital signals e₃ and holds these values until the next timing pulse ofg₁ is supplied. During the hold of the digital signal e₃, two digitalpicture signals having the same value are written into the memory 11with successive address numbers in synchronization with the twosuccessive address signals g₂ by the address signal generator 10according to the timing signal g₁ and the insert signal g₃.

Thus written picture signals into the memory 11 can be read out insynchronization with the reading out address signals g₂ ' producedaccording to the timing signals g₁ alone. Thereby the reproductiondigital picture signals e₄ are elongated with respect to the time axis.

The elongated reproduction digital picture signals e₄ are changed toanalog picture signals e₅ in synchronization with the timing signals g₁in the D-A converter 12. Hence, enlarged picture reproduction can beobtained.

The recording head 15 is moved faster than the scanning head 6 by theprescribed enlarged magnification scale which can be performed in thesame manner as in the case of picture reduction by, for example,controlling the rotating speed of the electric motor 5 by means of themagnification scale set up means 16.

The insert pulses g₃ are inserted among the timing signals g₁ at regularintervals in proportion to the reducing and enlarging magnificationscales. Therefore, in both the reducing and enlarging case, themagnification scale M is given by the ratio of the number of the writingaddress signals g₂ per unit time to the number of the reading outaddress signals g₂ ' per unit time. That is, the equation is as follows:

    M=g.sub.2 /g.sub.2 '

In FIG. 4, the magnification scale set-up means 16 comprises a presetcounter 17 counting the number of synchronous pulses g₁, an insert pulsegenerator 18 producing when a value counted by the preset counter 17coincides with a preset value corresponding to the desired magnificationscale, the insert pulses g₃ having proper wave forms and a magnificationscale setting means 19 having a preset dial, the presetting dial presetsrequired preset values to the preset counter 17 corresponding to themagnification scale.

Further, the magnification scale setting means 19 not only controls thetraversing speed of the scanning head 6 according to the magnificationscale set on the preset dial, but also selects whether the insert pulsesg₃ put out from the pulse generater 18 are fed to the writing circuitunit or to the reading out circuit unit of the address signal generator10 depending on whether the reproduction scale is greater or less thanunity, which is shown in FIG. 1 by a turn switch 20 for convenience.

The relation of the preset value n of the preset counter 17 to themagnification scale M is determined as follows: M is equal to the ratioof the number of address signals g₂, g₂ ' for writing and reading out,and one or the other of the address signals g₂, g₂ ' is the same as thetiming signal g₁. Accordingly, the following equations can be obtained:

    Reducing scale: g.sub.2 =g.sub.1, M=g.sub.2 /g.sub.2 '=g.sub.1 /g.sub.2 '=n/(n+1)

    Enlarging scale: g.sub.2 '=g.sub.1, M=g.sub.2 /g.sub.2 '=g.sub.2 /g.sub.1 =(n+1)/n

The equations mean that the preset counter 17 generates one insert pulseg₃ when it counts the number n of timing pulses g₁, and then theaddition of one insert pulse g₃ to the number n of the counted timingpulses g₁ results in the number (n+1) of address signals g₂ or g₂ '.Thereby the ratio n to (n+1) determines the magnification M. In FIG. 2for reducing scale, for example, the preset number n is three, and hencethe magnification scale is 3/4, and in FIG. 3 for enlarging scale themagnification scale is 4/3.

What is claimed is:
 1. In a picture reproducing method comprisingscanning an original picture to obtain picture signals to be recorded,correcting impurities of color ink components, generating timing pulsesin synchronism to a scanning speed, writing the picture signals into amemory including addressing said memory in synchronization with thetiming pulses, reading out the picture signals from the memory includingaddressing said memory in synchronization with the timing pulses, andrecording the reproduction picture from the picture signals read outfrom the memory; a method of varying reproduction scale, wherein eitherone of said steps of writing in or reading out memory address signalsincludes the step of addressing said memory with additional addresssignals synchronized to other pulses different from the timing pulses,said other pulses being inserted among the timing pulses withoutchanging a base frequency of said timing pulses.
 2. A picturereproducing method with variable reproduction scale according to claim1, wherein said other pulses are insert pulses generated by amagnification scale set-up means.
 3. A picture reproducing method withvariable reproduction scale according to claim 2, wherein said insertpulses are inserted among the timing signals at regular intervals inproportion to the magnification scale.
 4. A picture reproducing methodwith variable reproduction scale according to claim 2, wherein saidmagnification scale set-up means comprises a preset counter, an insertpulses generator responsive to said preset counter, and a magnificationscale setting means having a preset dial for presetting said presetcounter.
 5. A picture reproducing method with variable reproductionscale according to claim 4, wherein said magnification scale set-upmeans not only controls the travel speed of the scanning head asdetermined by the magnification scale fixed on the preset dial, but alsoselects whether the insert pulses are fed to a writing in or to areading out circuit unit of the address signal generator, correspondingto the enlarging or the reducing magnification scales.
 6. In a picturereproducing method comprising scanning an original picture to obtainpicture signals to be recorded, correcting impurities of color inkcomponents of the picture, generating timing pulses corresponding to ascanning speed, writing the picture signals into a memory includingaddressing said memory in synchronization with the timing pulses,reading out the picture signals from the memory including addressingsaid memory in synchronization with the timing pulses, and recording theoriginal picture from the picture signals read out from the memory; amethod of providing enlarged picture reproduction by generating insertpulses, addressing the memory in synchronization with the timing pulsesand the insert pulses, the insert pulses being inserted among the timingpulses after every predetermined number of the timing pulses, saidpredetermined number being in proportion to a desired enlargement scalewhen writing into the memory, writing the same picture signals asprevious picture signals to addresses addressed by the insert pulses,and reading out from the memory by addressing the memory insynchronization with only said timing pulses.
 7. In a picturereproducing method comprising scanning an original picture to obtainpicture signals to be recorded, correcting impurities of color inkcomponents of the original picture, generating timing pulsescorresponding to a scanning speed, writing the picture signals into amemory including addressing the memory in synchronization with certainpulses, reading out the picture signals from the memory with addressingin synchronization with the timing pulses, and recording the originalpicture from the picture signals read out from the memory; a method ofobtaining reduced picture reproduction by generating insert pulses,addressing the memory in synchronization with the timing pulses andinsert pulses, said insert pulses being inserted among the timing pulsesevery predetermined number of the timing pulses, some of said insertpulses being not in synchronization to the timing pulses, saidpredetermined number being in proportion to the desired reduction scalewhen reading out from the memory, erasing the picture signals read outfrom the addresses addressed by ones of said insert pulses not insynchronization with the timing pulses, and writing into the memoryincluding addressing in synchronization with only the timing pulses. 8.In a picture reproducing system comprising means for scanning anoriginal picture to obtain picture signals to be recorded, means forcorrecting impurities of color ink components of the original picture,means for generating timing pulses corresponding to a scanning speed,means for writing the picture signals into a memory including addressingsaid memory in synchronization with the timing pulses, means for readingout the picture signals from the memory including addressing said memoryin synchronization with the timing pulses, and recording thereproduction picture from the picture signals read out from the memory;a circuit for varying a reproduction scale, comprising means associatedwith said writing means or said reading means for addressing said memorywith additional address signals synchronized to other pulses differentfrom the timing pulses; and means for inserting the other pulses amongthe timing pulses without changing a base frequency of said timingpulses.